Re: Commits 8de72b and 5457a1 (COPY FREEZE)

On 21 December 2012 20:10, Noah Misch <noah(at)leadboat(dot)com> wrote:

> I thought of one case where we do currently forget rd_newRelfilenodeSubid:
>
> BEGIN;
> TRUNCATE t;
> SAVEPOINT save;
> TRUNCATE t;
> ROLLBACK TO save;

That's a weird one. Aborting a subtransacton that sets it, when it was
already set.

The loss of rd_newRelfilenodeSubid in that case is deterministic, but
tracking the full complexity of multiple relations and multiple nested
subxids isn't worth the trouble for such rare cases [assumption].

I'd go for just setting an its_too_complex flag (with better name)
that we can use to trigger a message in COPY to say that FREEZE option
won't be honoured. That would then be completely consistent, rather
than the lack of deterministic behaviour that Robert rightly objects
to.

--
Simon Riggs http://www.2ndQuadrant.com/
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